This invention relates to methods and systems to effect protocol segregation or separation in packet communications across networks, and more particularly, to a methodology and system for improving quality of service in the operation of hybrid networks, such as combined telephone networks and packet switched internetworks, such as the Internet. In one aspect the invention relates to an improved protocol separation or segregation mechanism and methodology for raising the speed of operation of packet networks handling real time as well as data service.
The potential development of telephony over the Internet technology as a viable commercial telephony service has attracted interest by equipment and software vendors as well as long distance and local exchange carriers. Recently the patent literature has begun to reflect an interest in aspects of such a service.
U.S. Pat. No. 5,726,984, issued Mar. 10, 1998, to Kubler, et al. entitled Hierarchical Data Collection Network Supporting Packetized Voice Communications Among Wireless Terminals and Telephones. That patent describes a packet-based communication system in which wired and wireless communication networks exhibiting substantially different characteristics are employed to link portable or mobile computing devices. The network accommodates real time voice transmission through a packet-based routing within a data network. Conversion and call processing circuitry enables access devices and personal computers to adapt voice information between analog voice streams and digital voice packet formats. Routing pathways include wireless spanning tree networks, wide area networks, telephone switching networks, Internet, etc. A voice session and associated call setup simulates that of conventional telephone switching network. Voice packets are queued in the receiving processors to take into consideration packet delivery delays within the Internet and prevent gaps in the delivered voice signals.
Other proposals have been made to deal with such delays. U.S. Pat. No. 4,538.259, issued Aug. 27, 1985, to Brian B. Moore entitled System for Digitized Voice and Data with Means to Compensate for Variable Path Delays. That patent describes a communication system in which voice is transmitted as packets of digitized samples and the receiving station delays the output of the first packet to compensate for wide variations in the intervals at which successive packets are received. According to one feature of this system, a first packet is transmitted at a higher priority so that a greater delay can be used without encountering problems that arise from the uncertainty in the delay in transmitting the packet. In another feature of this system, the arrival time of the first few packets of a conversation are detected and the delay is readjusted in case the first packet has been unusually delayed.
U.S. Pat. No. 5,724,355 issued Mar. 3, 1998 to Bruno et al. entitled Network Access to Internet and Stored Multimedia Access Services from a Terminal Supporting the H.320 Protocol. That patent describes a system for providing video conferencing services over the Internet.
In addition to the approaches to the packet delay problem addressed in the foregoing patents, there is also the problem of security. In providing a gateway between a secure network, such as a switched telephone network, and an unsecure network, such as the Internet, the protection and maintenance of network security immediately becomes a concern. Protecting a secure network from unauthorized use or attack is of paramount importance to any organization. When the secure network constitutes the public switched telephone network (PSTN) the seriousness of the threat is self-evident. In communicating with essentially real time applications such as telephony via packets, there is a need for both consistency and speed. The packets must arrive on a consistent basis and they must arrive quickly. However, generally speaking, when any type of security scheme is implemented, some latency or inconsistency is introduced into the data stream. When a very limited number of streams are involved the problem is manageable. However, as the number of streams starts increasing it is much more difficult to provide adequate security at an acceptable cost without introducing quality of service problems.
It is a primary object of the invention to provide a new mechanism and methodology for coping with and alleviating the latency problem encountered in packet communication when handling substantially real time applications.
It is another object of the invention to provide a new process for transporting a stream of packetized data including packets of different protocols by determining at least part of a byte in the packets which characterizes a selected one of the protocols, monitoring the stream to detect the occurrence of that part of a byte, and diverting packets containing the part of a byte from the stream.
It is yet another object of the invention to provide a novel protocol separator having a processor with an input port and output ports, and data links connected to the input port to the outputs port, with the data link to the input port carrying packetized data including packets of different protocols, the data link to one of the output ports carrying packets of a first protocol removed from the stream by the processor, and with the data link connected to the other output port carrying the remainder of the packets delivered to the input port.
According to a preferred embodiment of the invention, a protocol separator which includes a processor is provided and has an input port and output ports, with data links connected to the ports. The data link to the input port carries a stream of packetized data input, which includes packets of different protocols. Packets of a selected protocol are removed from the stream by the processor and outputted via one of the output ports and links. The remainder of the input stream is outputted via the second output port and link. The protocol separator operates by determining at least part of a byte in the selected protocol packets which characterizes that protocol, monitoring the incoming stream to detect the occurrence of that part of a byte, and diverting packets containing the part of a byte from the stream to the first output. The remainder of the stream is fed to the second output.